中子探测仪在林地土壤水分研究中的应用

<正> 目前对土壤水分的研究可以分为两大类:一类是空间变异性问题,即对同一时刻不同位置的土壤水分特征值进行估计,另一类是时间变化问题,即对同一位置不同时刻的土壤水分特征值进行研究。 自1952年Gardner和Kirkham开创性地应用中子探测仪测定土壤水分的变化之后,中子探测仪成为比较通用的野外原状土壤含水量的探测仪器。该仪器能较准确地探测出土壤水分的时间变化过程,因此使得从短期内土壤水分平衡的角度来推算蒸发散量成为可能。 对于土壤性质的空间变异性研究,从本世纪初就已开始,特别是60年代以后,这方面的研究已进一步深入化。研究者们希望了解土壤特征参数在什么条件下才

Application of Neutron Probe in the Study of Soil Moisture on Forest Land

Neutron probe has been commonly used to measure in situ the water content of soil since 1952. The author made a study of the distribution and variation of soil moisture on forest land according to the data measured by neutron probe only. The results indicated that the spatial distribution of soil moisture on forest land had temporal stability. That is to say, the temporal variation of soil water content had spatial correlation. According to this,the temporal variation of the average soil water content on the forest land could be determined by the known variation of soil water content at any point. It was also shown that the evapotranspiration on forest land could be calculated directly from the neutron probe measurement at places where no surface runoff and subsurface flow as well as percolation in deep layer took place, and also, where the interception of precipitation by vegetation could be estimated.